The present invention relates generally to concrete, and more particularly to surface seeded exposed aggregate concrete and a method of forming the same.
As is well known in the building and construction trade, concrete is extensively utilized as a building material for industrial, commercial and residential applications. Due to its durability, wear resistance and cost economy, concrete is currently gaining widespread use in flooring applications. With this widespread use, the public is currently demanding variations in color and surface texture of concrete such that the concrete possesses improved aesthetics similar to more conventional and costly flooring surfaces such as marble, stone and granite.
To meet this demand, the concrete trade has previously developed various coloring and surface finishing techniques to enhance the aesthetics of the concrete. Examples of such finishing techniques include salt finish, multiple broom finish, form press finish (e.g., stamped concrete), and exposed aggregate finish.
With particular regard to exposed aggregate finishes, one of two different production methods or techniques are typically utilized to form the same, i.e., the integrally exposed aggregate method and the surface seeded exposed aggregate method. The more conventional of these two techniques is the integrally exposed aggregate method which comprises the washing or removal of the surface cement and fines from the concrete while the concrete surface is still plastic (i.e., before full curing) such that the aggregate (which is normally rock or gravel) is left exposed on the surface of the concrete. Due to the normal size of such concrete aggregate being relatively large (i.e., approximately one-half to one inch in mean diameter) as well as the washing process not being uniform in nature, the resultant concrete surface derived by the integrally exposed aggregate method is extremely rough and jagged, thereby limiting its wide-spread use in flooring applications.
More recently, the surface seeded exposed aggregate method has been introduced into the trade. In this particular method, subsequent to the pouring of the concrete, rock or gravel aggregate is broadcast (i.e., seeded) over the top surface of the concrete and subsequently troweled into the same. Upon the curing of the concrete, the aggregate broadcast over the top surface thereof is adhered thereto and thus exposed. Although various size aggregate can be broadcast over the top surface of the concrete in the surface seeded exposed aggregate method, such aggregate is normally of about a three-eighths inch diameter or greater mean size having sheared or jagged edges such that the same can be worked into the top surface of the concrete and adequately adhered thereto. Thus, the resultant concrete surface, although being flatter and not possessing as many surface irregularities as the integrally exposed aggregate surface, still possesses an extremely rough surface which limits its widespread use in flooring applications.
In recognition of the above-described deficiency, attempts have been made in the prior art to reduce the size of the aggregate exposed on the surface of the concrete. However, such proposed solutions have typically failed due to the inability in adhering such smaller aggregate to the concrete surface. In this regard, as the aggregate size diminishes, it has been extremely difficult to insure that the aggregate will be adequately maintained upon the surface of the concrete for a prolonged duration and with substantial uniformity.
To overcome this deficiency, Applicant developed an improved exposed aggregate concrete finishing technique which maintains sufficient flatness and possesses minimal surface roughness so as to be suitable for pedestrian high traffic flooring applications. This technique is described in Applicant's U.S. Pat. No. 4,748,788 entitled SURFACE SEEDED EXPOSED AGGREGATE CONCRETE AND METHOD OF PRODUCING SAME, the disclosure of which is incorporated herein by reference. Though Applicant's technique as described in U.S. Pat. No. 4,748,788 overcame many of the deficiencies of the prior art surface seeded exposed aggregate method, Applicant has now developed improvements to such technique which facilitate a more even and uniform top surface texture and greater adhesion of the aggregate thereto. This refined technique allows materials including glass bead and silica sand to be used as the aggregate. These and other advantages related to the present invention will be described in more detail below.